The progressive awareness of public administrations and society towards the necessity of preserving the cultural heritage, particularly rock art, has become more and more important in developed countries. In Galicia (northwest of Spain),... more
The progressive awareness of public administrations and society towards the necessity of preserving the cultural heritage, particularly rock art, has become more and more important in developed countries. In Galicia (northwest of Spain), there are many petroglyph remains that are seriously affected by a severe acceleration in degradation due to urban expansion. In this situation, actions focused on the preservation of these patrimonial elements have to be accomplished. These protection forms must be preceded by a previous step of exhaustive documentation of the prehistoric element, in order to register the conservation state of the element so that it can be contrasted with future observations or studies. The advances experimented by 3D digital techniques make possible to document rock art avoiding the inconveniences previously mentioned. The 3D digitalization of objects allows not only registering the metric and radiometric characteristics of objects, but also the diffusion and tran...
Universitario As Lagoas –Marcosende s/n 36200 Vigo Spain – (belenriveiro, parias, julia, firv, merchisolla)@uvigo.es Commission V, WG V/2 ABSTRACT: This paper describes the project of the Close Range Photogrammetry and Remote Sensing... more
Universitario As Lagoas –Marcosende s/n 36200 Vigo Spain – (belenriveiro, parias, julia, firv, merchisolla)@uvigo.es Commission V, WG V/2 ABSTRACT: This paper describes the project of the Close Range Photogrammetry and Remote Sensing Group, University of Vigo, Spain, involving historic arch bridges in Galicia, Spain. The first aim of this Project consists on building a database of the historic arch bridges in Galicia, documenting location, surroundings, geometry, singular characteristics, structural faults, building material and state of conservation. On the other side, a methodology is being designed to optimize measuring and analysing techniques: Close Range Photogrammetry and Laser Scanning as 3D modelling tools for geometry and cracks documentation (Arias et al, 2005), Ground Penetrating Radar for inner material characterization and zones description, and FEM as structural analysis tool to establish stress distribution compatible with the detected damages, allowing identifying i...
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ABSTRACT The use of Building Information Models (BIM) for energy analysis is becoming a common application, supported by the appearance of standards and regulations restricting energy consumption and energy efficiency in the building... more
ABSTRACT The use of Building Information Models (BIM) for energy analysis is becoming a common application, supported by the appearance of standards and regulations restricting energy consumption and energy efficiency in the building sector. BIMs from already built buildings are being generated with the help of high-technology devices such as laser scanners, which acquire the physical reality of a scene with high accuracy in a short time. However, the environment of the building, and especially surfaces producing shades, which are essential for the performance of meaningful energy studies, is usually forgotten as the focus is set on the representation of complex geometries. With the aim of generating a BIM able to be subjected to energy analysis, this paper presents a working methodology including data acquisition with a laser scanner, shape extraction of the building itself and its surroundings, and conversion of extracted elements, including shade surfaces, to BIM components.
ABSTRACT This paper presents a working methodology for the automatic generation of as-built Building Information Models (BIMs) including shade surfaces able to be subjected to solar analysis, given the great effect that shading has in the... more
ABSTRACT This paper presents a working methodology for the automatic generation of as-built Building Information Models (BIMs) including shade surfaces able to be subjected to solar analysis, given the great effect that shading has in the energy consumption of the building. This methodology goes from data acquisition with a laser scanner, to the shape extraction of the building and its surroundings from the acquired data through curvature analysis and Region Growing algorithms, to end with the conversion of the extracted elements, which define both the building and the shading elements, to BIM components. BIM is defined in gbXML language, which was especially designed to be used in energy software, so that the generated BIM with shades can be directly introduced in energy analysis software.
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ABSTRACT Monitoring of breakwaters is a key aspect to prevent failures that affect the safety and quality of service. Unmanned aerial vehicle (UAV) photogrammetry gives low-cost and accurate geometric data, flexibility, and productivity... more
ABSTRACT Monitoring of breakwaters is a key aspect to prevent failures that affect the safety and quality of service. Unmanned aerial vehicle (UAV) photogrammetry gives low-cost and accurate geometric data, flexibility, and productivity to perform aerial surveys, although the weather conditions restrict flights for wind speeds above 50 km/h (the Mikrokopter system). Despite the promising potential of these systems, its ability to monitor movement of cubes in breakwaters has not yet proven. The UAV photogrammetry is tested for the research reported in this paper in the Baiona breakwaters (northwestern Spain). A SD of 0.026 m is obtained from the point cloud. The detection limit of the system is evaluated and rotations lower than 1° could be detected. This value is calculated from the measurable differences in height values after the virtual rotation of a single cube. The system provides the exact position where the movement of the cube is produced and can be easily integrated with geographic information system–based management systems.
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A low-cost mechanical artifact is developed for the metrological verification of photogrammetric measurement systems. It is mainly composed of five delrin spheres and seven cubes manufactured in different sizes. A set of circular targets... more
A low-cost mechanical artifact is developed for the metrological verification of photogrammetric measurement systems. It is mainly composed of five delrin spheres and seven cubes manufactured in different sizes. A set of circular targets are fixed on these elements to perform the photogrammetric restitution. The artifact is used in order to compare three photogrammetric systems defined by three different cameras
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The calibration of the cameras used in close-range photogrammetry is usually performed using auxiliary elements with known geometry and/or dimensions, through one or several photographs of elements with geometrical restrictions, which... more
The calibration of the cameras used in close-range photogrammetry is usually performed using auxiliary elements with known geometry and/or dimensions, through one or several photographs of elements with geometrical restrictions, which enable the calculation of the different parameters needed. This research suggests an improvement in these procedures through the use of one or several laser meters. The method is based on the use of calibration pillars in a laboratory, in which the cameras and laser meters subject to calibration are fixed. The cameras are calibrated by determining the relative positions of all the devices at the same time, which enables the application of the algorithm designed for hybrid laser-camera systems used for measuring in civil engineering and robotics. For this purpose, photographs and measurements are taken by laser meters over a moving object of unknown geometry and dimensions.
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ABSTRACT The data provided by three different measurement instruments, terrestrial laser scanning, image measurement from rectified photographs and 3D ground-penetrating radar, are compared and analysed in this work. For this purpose, an... more
ABSTRACT The data provided by three different measurement instruments, terrestrial laser scanning, image measurement from rectified photographs and 3D ground-penetrating radar, are compared and analysed in this work. For this purpose, an experimental grave is prepared using human bone remains and a pig carcass.A comparison of the geometrical data collected from the bone remains using laser scanning and single-image rectification show an agreement better than 4% for bones longer than 75 mm, which confirms the possibility of using the low cost image measurement technique for forensic purposes.The volume and weight of the pig carcass is also evaluated using the laser scanning data and a surface model fitted to the point cloud. The obtained result matches with the real data provided by the veterinarian. However, care must be taken to avoid the occlusions of the laser data, which could artificially increase the volume.The ground-penetrating radar survey clearly reveals the place where the pig is buried. The cross-sectional area is evaluated. The volume of the pig detected by GPR was determined and compared with the value obtained from the laser scanning. The results show a difference of about 25%.The ground-penetrating radar survey also shows some evidence of the cranium from the bone remains in the grave. However, the results are not clear, which demonstrates that the reliability of this technique decreases when the tissues of the cadaver are completely degraded.
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Many researchers have been working in Spain to document the communal graves of those assassinated during the Spanish Civil War. This article shows the results obtained with two low-cost photogrammetric techniques for the basic... more
Many researchers have been working in Spain to document the communal graves of those assassinated during the Spanish Civil War. This article shows the results obtained with two low-cost photogrammetric techniques for the basic documentation of forensic studies. These low-cost techniques are based on single-image rectification and the correction of the original photo displacement due to the projection and perspective distortions introduced by the lens of the camera. The capability of image rectification is tested in an excavation in the village of Loma de Montija (Burgos, Spain). The results of both techniques are compared with the more accurate data obtained from a laser scanner system RIEGL LMS-Z390i to evaluate the error in the lengths. The first technique uses a camera situated on a triangle-shaped pole at a height of 5 m and the second positions the camera over the grave using a linearly actuated device. The first technique shows measurement errors less than 6%, whereas the second shows greater errors (between 8% and 14%) owing to the positioning of the carbon-fiber cross on an uneven surface.
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... 19893. Alvarado-Blanco, S., Durán-Fuentes, M. and árdiz-Ortiz, CN 1989. ... View all references), including updating current evaluations of the state of conservation (Arias et al 20075. Arias, P., Di-Capua, D., Armesto, J.,... more
... 19893. Alvarado-Blanco, S., Durán-Fuentes, M. and árdiz-Ortiz, CN 1989. ... View all references), including updating current evaluations of the state of conservation (Arias et al 20075. Arias, P., Di-Capua, D., Armesto, J., González-Drigo, R., Lorenzo, H. and érez-Gracia, VP 2007. ...
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Research Interests: Civil Engineering, Structural Dynamics, Finite element method, Structures and Fire Engineering, Ground Penetrating Radar, and 10 moreSensitivity Analysis, Finite Element, Finite Element Analysis, Laser Scanning, Data Collection, Laser scanner, Dynamic Response, Multidisciplinary Approach, Material Properties, and Structural model
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Masonry arches are one of the most common and extended structural shapes present in the worldwide architectural heritage. When handling with these structures at least two demands are addressed to the scientific community: (i) development... more
Masonry arches are one of the most common and extended structural shapes present in the worldwide architectural heritage. When handling with these structures at least two demands are addressed to the scientific community: (i) development of reliable and affordable methods for documenting historic infrastructures and (ii) improvement of structural analysis for appraising the actual structural condition of the bridge. In
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ABSTRACT Building Information Models are being increasingly accepted as containers and managers of data during the lifecycle of buildings, given their capacity of associating the descriptive data available, such as the physical properties... more
ABSTRACT Building Information Models are being increasingly accepted as containers and managers of data during the lifecycle of buildings, given their capacity of associating the descriptive data available, such as the physical properties of the materials, with the 3D representation of the building. In the case of existing buildings, as-built BIMs have to be created, and non-destructive techniques are required to acquire all the information needed provoking no disruption or change to the building. In this work, the as-built BIM of a facility is created through the semi-automated processing of a laser scanning point cloud and enriched with the different U-values of the enclosure. This thermophysical property is obtained for the construction as-is through an energy balance using temperature values measured with a thermographic camera. The resulting as-built BIM is defined according to the gbXML language, which was especially created to be used in analysis of the performance of the building.
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ABSTRACT Mobile LiDAR systems are being used widely in recent years for many applications in the field of geoscience. One of most important limitations of this technology is the large computational requirements involved in data... more
ABSTRACT Mobile LiDAR systems are being used widely in recent years for many applications in the field of geoscience. One of most important limitations of this technology is the large computational requirements involved in data processing. Several software solutions for data processing are available in the market, but users are often unknown about the methodologies to verify their performance accurately. In this work a methodology for LiDAR software performance testing is presented and six different suites are studied: QT Modeler, AutoCAD Civil 3D, Mars 7, Fledermaus, Carlson and TopoDOT (all of them in x64). Results depict as QTModeler, TopoDOT and AutoCAD Civil 3D allow the loading of large datasets, while Fledermaus, Mars7 and Carlson do not achieve these powerful performance. AutoCAD Civil 3D needs large loading time in comparison with the most powerful softwares such as QTModeler and TopoDOT. Carlson suite depicts the poorest results among all the softwares under study, where point clouds larger than 5 million points cannot be loaded and loading time is very large in comparison with the other suites even for the smaller datasets. AutoCAD Civil 3D, Carlson and TopoDOT show more threads than other softwares like QTModeler, Mars7 and Fledermaus.
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ABSTRACT Geometry of buildings is an essential measurement during energy inspections, since it has a great influence in the energy performance of the building. Given the difficult access presented to some areas of the buildings that make... more
ABSTRACT Geometry of buildings is an essential measurement during energy inspections, since it has a great influence in the energy performance of the building. Given the difficult access presented to some areas of the buildings that make impossible their complete geometric characterization with terrestrial devices, Unmanned Aerial Vehicles (UAVs) stand as the solution for the acquisition of data both from façades and roofs. In this paper, the potential of UAV to building geometric inspection is analyzed by mounting a Kinect sensor for geometric data acquisition in three-dimensions. The resulting point cloud and 3D model are evaluated in order to validate the performance of the complete system.
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ABSTRACT Infrared thermography has proved to be an adequate technique for building inspection, as it can be used to determine energy efficiency and also to detect defects in construction. Geometry and spatial relationships are also very... more
ABSTRACT Infrared thermography has proved to be an adequate technique for building inspection, as it can be used to determine energy efficiency and also to detect defects in construction. Geometry and spatial relationships are also very important in building inspection because they make location of thermal defects and measurement of affected surfaces possible. A procedure to fuse automatically generated infrared mosaics and visible images to combine geometric information with thermal data in the same image is described in this paper. Fused images are then used for the automatic generation of a thermographic 3D model of the building through image matching, where apart from having thermographic information available, geometric measurements can be performed. The proposed methodology is suitable for building inspection, where working space and time are usually limited so a reduction on the number and size of instruments is appreciated. Furthermore, automation of the process diminishes the error in results by avoiding operator's influence.